NASA’s Juno spacecraft, which has been orbiting Jupiter since 2016, has revealed new insights into the similarities and differences between the lightning processes on the gas giant and our own planet.
Jupiter is the largest planet in our solar system, with a diameter of about 140,000 kilometers (87,000 miles), more than 11 times that of Earth. It is also a very different world, with no solid surface and a thick atmosphere composed mainly of hydrogen and helium.
However, hidden below the brownish ammonia clouds that cover Jupiter are water clouds that resemble those on Earth. And like on Earth, these clouds can generate lightning - an electric discharge that can be seen as bright flashes in the dark Jovian sky.
Lightning was first detected on Jupiter in 1979 by NASA’s Voyager 1 spacecraft, which recorded radio emissions at audible frequencies as it flew past the planet. Since then, other spacecraft have confirmed the presence of lightning on Jupiter, as well as on the other gas planets - Saturn, Uranus and Neptune.
Using five years of high-resolution data collected by Juno’s radio receiver, a team of researchers has found new evidence that the lightning initiation processes on Jupiter pulsate with a similar rhythm to those observed inside Earth’s clouds.
The researchers analyzed the time intervals between successive lightning flashes recorded by Juno and found that they were typically around one millisecond, similar to thunderstorms on Earth.
“This means that the physical mechanism that initiates lightning inside Jupiter’s clouds is very similar to what happens inside Earth’s clouds,” said Ivana Kolmasova, a planetary scientist at the Czech Academy of Sciences’ Institute of Atmospheric Physics in Prague and the lead author of the study published this week in the journal Nature Communications.
Lightning is caused by the separation of electric charges within clouds. When ice and water particles collide inside a cloud, they can transfer electrons and create layers of particles with opposite charges. This builds up a huge electric field that can eventually trigger a discharge.
However, there are also some differences between the lightning processes on Jupiter and Earth. For example, Jupiter’s lightning flashes are much more powerful and last longer than those on Earth. They also occur more frequently at higher latitudes and closer to dawn than on Earth.
The researchers said these differences could be explained by the different atmospheric dynamics and composition on Jupiter. For instance, Jupiter’s faster rotation and stronger Coriolis force could affect the distribution and movement of thunderstorms on the planet.
The researchers also said that studying lightning on Jupiter could help them understand more about the planet’s water cycle and climate.
“Lightning is a very important indicator of water in Jupiter’s atmosphere,” said Kolmasova. “Water is essential for life as we know it, so understanding how much water there is on Jupiter and how it behaves can give us clues about the origin and evolution of our solar system.”
